What

Trying to help out a friend here at our shop and we've been doing a little playing around on his TT LS1 (we built the kit... two T3/T4Es) with LS1 edit. Thanks to NoGo for answering a few quick questions on the phone last week btw-. The few quick minutes on the phone helped out a lot.

Anyways, our bud ran the turbos with no LS1edit and 8psi and no surprise, blew up a few pistons. We convinced him to put on some heads from a 6.0L to drop compression and have the bigger valves and while he is dumping more money into a built motor elsewhere he put this one put back together on the bottom end he originally fried himself (just with other stock pistons). While summer is here, he wants to take advantage of it. Which may sound like a good idea, but it's hard to get him to slow down and take it one step at a time.

He has a 5 wire wb02, but hasn't even picked up anything to datalog knock or have EGTs, or... so on. Unfortunately our shop is the only performance shop within a few hundred kms and we are engineering a chassis dyno for our use, but it will not be ready for a while. Why all this? Basically, because neither him nor I have the ability to datalog and do all the wonderful things that would make life easy for tuning at teh moment. So, please excuse the somewhat old school 'seat o pant' tuning.

So at any rate, my basic question is what kind of timing are you guys running with the 6.0L heads? This low compression version felt like a dog at 8psi compared to the old high compression motor to begin with.... which was mostly me starting out with conservative timing map. Picked up some of the old throttle response before boost by advancing the timing to get things moving, and expirmented from there. After a bunch of playing around, getting fuel about 11-11.5:1 all the way in boost that we can tell (wb02 but not datalog.. may not be seeing all the data), the timing values where this thing goes like a beast once more seems simply wayyy to high considering that I read of values of only 14 degrees on here. I'm just wondering if I'm way off base here and should not go by what feels good and keep the timing back in case she blows.

No audible detonation doesn't mean there isn't detonation...

but...

just because a knock sensor registers knock, doesn't mean that little piezo-electric device is picking up some other fuzz that is not truly knock.

twin stock fuel pumps, 48lb/hr injectors, boost is building by about 2100-2200rpm, and full boost by early as 2700rpm-2800rpm on the new heads. Boost holds to redline, and can handle more flow and pressure still (changed springs in wastegate, but don't really have a boost controller I'd consider playing with). Right now the boost curve is dead accurate with the two wastegates controlling the boost.

Comments/suggestions?

What

oh, we were testing on pump gas. Conversion is in an 82 camaro, Lingenfelter intake (no idea which one... like I say, he's more of a friend and I don't usually work on domestics, so just getting used to LS1edit has been and still is a learning curve). Subframe has been added to increase strength for his future goals... but future goals are a discussion for another thread.

MYTURBOT/A

With my 6.0s i'm running 16* at 4000rpm (TQ peak) ramping up to 20* at 6000 rpm This is at 13psi boost. Running 8 psi i don't see why you couldn't run around 18*-23* being conservative. Good luck.

S_J_H

What, How much timing are you guys running?
I use 22' up top and 18' at TQ peak with 13psi.
I gave up on the K.S. a while ago. After still seeing Knock activity at 14' peak timing, 100 octane gas and the blower belt removed, I pretty much confirmed the fact they are useless POS that have no place on a high perf motor.

ChevyNo1

Steve! How can you tell if you have knock then? I had disabled my sensors because the PCM thought they were garbage, even after replacing them. I had no audible knock, but somehow still got it and cracked #1 ringland. How can you be sure if you're not guaranteed that you'll hear it??

- Dug

Ed Blown Vert

iTrader: (2)

I though you would ramp down on the timing?
I went from 20 to 17*

ChevyNo1

You ramp down as you approach peak TQ, ramp up slowly after that . . .

What

Ah, thanks very much. These replies make me feel wayyy better. I have around 4-5 degrees more than stock timing before the turbo spools (function of the head and compression), and then ramp down to 18degrees around 4000rpm... which was my guess at where peak torque would be around from the drives, and then ramp back up to 22 degrees to keep power from falling off.

It was running beautiful... with 3 guys in the car, it would have pulled some good times at the track. We were trying to get him a little more power so we tried swapping out the wastegate springs but it went up to 12psi or so. Sounded clean still, but ran into some other tuning issues with LS1 that I have to figure out.

DIY knock detection- I saw this article on autospeed a while back and built myself one. I like the theory of the human ear being able to better decipher sounds than a factory knock sensor. Only difficulty being, it should be connected where factory knock sensors are, and in this case, I'm not taking off his intakes to attach it and never get it back. I haven't had much opportunity to check if it does indeed work as well as they say as you hear so much valve train noise and I haven't tried to tune anything to the knock range just to see... It does work well as an electronic stethoscope at minimum although I can't reccomend at this point to do it for sure to check for knock. If someone has tooo much time on there hands like I did, they may want to try it.

http://www.autospeed.com/A_0348/cms/article.html

Ed Blown Vert

iTrader: (2)

Thanks!

ChevyNo1

You're welcome! And some people keep timing the same from peak TQ to redline . . . I brought mine slowly back in.

- Dug

MYTURBOT/A

Yea with turbos you have full boost around 3000-3500rpm which is usually where the tq peak is. Where a blower makes more boost as the rpms go meaning you'll pull more timing as the boost goes up.

SJH I ve ran as much as 18* at TQ peak but after floging the car for awhile in the florida heat i'd start seeing KR. So I backed it down to 16 now i can beat the crap out of it on 93 octain all day with 0 KR and coolant temps around 230*F with the A/C on. I've got a race fuel tune that is for 104 unleaded which has 21*-26*.

It really depends alot on boost pressure, fuel octain, Intake temps and compression.